U.S. Pat. No. 6,808,955 discloses a method of mounting, in connecting an MEMS chip and an IC chip, the MEMS chip face-down on the IC chip to reduce a wiring path between the MEMS chip and the IC chip.
However, in the method disclosed in U.S. Pat. No. 6,808,955, because the MEMS chip is mounted face-down on the IC chip, a wire cannot be directly connected from the MEMS chip to the outside of a package. To connect the wire from the MEMS chip to the outside of the package, the wire needs to be connected through the IC chip. Therefore, parasitic capacitance is formed between the MEMS chip and the IC chip and noise is caused between the MEMS chip and the IC chip. As a result, it is difficult to handle a high-speed signal and an analog signal.
Further, in the method disclosed in U.S. Pat. No. 6,808,955, because the MEMS chip is mounted face-down on the IC chip, the IC chip cannot be flip-chip mounted on a mother board. To connect a wire from the IC chip to the outside of the package, wire bonding needs to be used. Therefore, parasitic inductance increases and characteristic impedance cannot be matched. As a result, it is more difficult to handle a high-speed signal and an analog signal.